Video signals are used in many applications, including security, TV, Internet entertainment, and the like. Closed Circuit Television (CCTV) is an application that allows a video signal from a camera to be viewed by a person/user on a television set, typically at a nearby location. For example, a building may have one or more video cameras on the outside or at entry points for security purposes and a user views the video signal from the cameras on a TV inside the building. In this context, CCTV systems may be used for security purposes in commercial or residential buildings where the CCTV feed is typically monitored by security personnel or an automated system. CCTV is also used, for example, by residents of a multi-dwelling unit (MDU), such as a condominium or apartment building, to view an internal video signal (video feed) provided from one or more security cameras at the building entrance(s) allowing the residents to view visitors before determining whether or not to let the visitor enter the building.
In most residential and some commercial applications, CCTV signals are typically provided through television channels. Cable companies providing an analog television service to customers living in MDUs often offer to integrate the local CCTV signal in their own cable feed. This is usually accomplished by filtering the incoming cable television signal to remove one channel therefrom and substituting in its place the properly modulated CCTV signal before distribution to the subscribing unit of the MDU. In this situation, subscribers/residents can tune into a dedicated channel providing continuous lobby entrance real time video feed. Any resident can view the camera at any given time, and see who is at the MDU lobby.
When dealing with fully digital TV, this approach can be more difficult, because a locally connected CCTV signal cannot efficiently be simultaneously broadcast to all units of an MDU. Further, as the incoming digital signal is only decoded at the set top box in each subscribing unit. In order to properly encode the CCTV signal and integrate it in the regular digital television feed, one approach has been to send the local, unencoded CCTV signal from the MDUs to the closest headend, where the CCTV signals from all the subscribing MDUs serviced by the same headend are digitally encoded and multiplexed with the entire broadcasted digital television feed. From there, the resulting television feed is sent to all subscribing customers through various central offices. Although only the units of a particular MDU are allowed to see the CCTV signal from their local camera, the same signal is actually received by every subscriber in a large area, creating a waste of bandwidth, and making this technique difficult to apply to a large scale.
There remains a need for an efficient and relatively simple system and method for providing video signal delivery, particularly in the case of physical access control systems.